Shear Ram Blowout Preventer with Engagement Feature

ABSTRACT

A blowout preventer (“BOP”) includes a housing comprising a vertical bore extending through the housing, and a pair of opposing shear rams configured to move into the vertical bore. The shear rams comprise an engagement feature configured to engage with a corresponding engagement feature and urge the shear rams into axially towards each other with respect to an axis of the vertical bore when the shear rams are located in the vertical bore.

BACKGROUND

This section is intended to provide background information to facilitatea better understanding of the various aspects of the describedembodiments. Accordingly, it should be understood that these statementsare to be read in this light and not as admissions of prior art.

Blowout preventers are used extensively throughout the oil and gasindustry. Typical blowout preventers are used as a large specializedvalve or similar mechanical device that seal, control, and monitor oiland gas wells. The two categories of blowout preventers that are mostprevalent are ram blowout preventers and annular blowout preventers.Blowout preventer stacks frequently utilize both types, typically withat least one annular blowout preventer stacked above several ram blowoutpreventers. The ram units in ram blowout preventers allow for both theshearing of the drill pipe and the sealing of the blowout preventer.Typically, a blowout preventer stack may be secured to a wellhead andmay provide a safe means for sealing the well in the event of a systemfailure.

A typical blowout preventer includes a main body with a vertical bore.Ram bonnet assemblies may be bolted to opposing sides of the main bodyusing a number of high tensile bolts or studs. These bolts are requiredto hold the bonnet in position to enable the sealing arrangements towork effectively. Typically an elastomeric sealing element is usedbetween the ram bonnet and the main body. There are severalconfigurations, but essentially they are all directed to preventing aleakage bypass between the mating faces of the ram bonnet and the mainbody. Each bonnet assembly includes a piston which is laterally movablewithin a ram cavity of the bonnet assembly by pressurized hydraulicfluid acting on one side of the piston. The opposite side of each pistonhas a connecting rod attached thereto which in turn has a shear ram andcorresponding blades mounted thereon.

These rams are designed to move laterally toward the vertical bore ofthe blowout preventer to shear or cut any object located therein. Forinstance, the rams can close in on and shear a tubular within thevertical bore of the blowout preventer, such as a section of drill pipeused during drilling operations. The opposing rams typically experiencesome axial separation after shearing, such as when shearing a largerobject (e.g., a tool joint) or wireline. The axial separation resultsfrom shear forces encountered when shearing the object, leaving avertical gap between the opposing shear blades. This vertical gapbetween the shear rams or blades may then make it difficult to seal orsubsequently shear objects with the blowout preventer. Accordingly, amechanism for enabling shear rams to more efficiently seal or shear in ablowout preventer bore may be desirable.

DESCRIPTION OF THE DRAWINGS

For a detailed description of the embodiments of the invention,reference will now be made to the accompanying drawings in which:

FIGS. 1A-1C depict multiple cross-sectional views of a blowout preventerfor shearing a tubular, according to one or more embodiments;

FIG. 2 depicts a side perspective view of shear rams, according to oneor more embodiments;

FIG. 3 depicts a top down view of the shear rams, according to one ormore embodiments;

FIG. 4 depicts a cross-sectional view of the shear rams taken along line4-4 in FIG. 2, according to one or more embodiments;

FIG. 5 depicts a detailed view of the engagement of the shear rams inFIG. 4, according to one or more embodiments;

FIG. 6 depicts a cross-sectional view of the shear rams taken along line6-6 in FIG. 2, according to one or more embodiments; and

FIG. 7 depicts a detailed view of the engagement of the shear rams inFIG. 5, according to one or more embodiments.

DETAILED DESCRIPTION

Referring now to FIGS. 1A-1C, multiple views of a blowout preventer(“BOP”) 10 for shearing a tubular D in accordance with one or moreembodiments of the present disclosure are shown. The BOP 10, which maybe referred to as a ram BOP or shear ram BOP, includes a body 12 with avertical bore 14 formed and/or extending through the body 12. As shown,the body 12 includes a lower flange 16 and/or an upper flange 18 tofacilitate connecting the BOP 10 to other BOPs or other components, suchas a wellhead connector on the flower flange 16 or to a lower marineriser package on the upper flange 18. Ram cavities 20 and 22 are formedwithin the body 12 of the BOP 10, with the cavities 20 and 22intersecting and extending outwardly from the bore 14 on opposite sidesof the BOP bore 14.

The BOP 10 includes one or more rams or ram assemblies, such as a firstram 24 and a second ram 26. The first ram 24 may be positioned andmovable within the first cavity 20 and a second ram 26 positioned andmovable within the second cavity 22. The first ram 24 and the second ram26 are positioned to oppose each other (e.g., on opposite sides of thebore 14) and are movable towards and away from the tubular D. Actuators28 are provided to move the first ram 24 and the second ram 26 into theBOP bore 14 to shear the portion of the tubular D extending through theBOP bore 14.

In this embodiment, a hydraulic actuator is shown, though any type ofactuator (e.g., pneumatic, electrical, mechanical) may be used inaccordance with the present disclosure. The actuators 28 shown in thisembodiment include a piston 30 positioned within a cylinder 32 and a rod34 connecting the piston 30 to each respective ram 24 and 26. Further,pressurized fluid is introduced and fluidly communicated on oppositesides of the piston 30 through ports 35, thereby enabling the actuator28 to move the rams 24 and 26 in response to fluid pressure.

A first (e.g., upper) blade 36 is included with or connected to thefirst ram 24, and a second (e.g., lower) blade 38 is included with orconnected to the second ram 26. The first and second blades 36 and 38are formed and positioned such that a cutting edge of the second blade38 passes below a cutting edge of the first blade 36 in shearing of asection of a tubular D. The shearing action of first and second blades36 and 38 shear the tubular D. The lower portion of the tubular D maythen drop into the well bore (not shown) below BOP 10, or the lowerportion of tubular D may hung off a lower set of rams (not shown).

Accordingly, disclosed herein are a BOP apparatus and/or a ram for a BOPapparatus for shearing an object located therein. The object may bepositioned within the bore extending through the BOP, in which the BOPis actuated to move one or more rams to engage and shear the object. Aram of a BOP in accordance with the present disclosure may be used forshearing one or more different types of objects that may have differentshapes, sizes, thicknesses, and other dimensions and properties.

For example, an object may include a drill pipe joint, a casing joint, atool joint, or a wireline, in which a BOP in accordance with the presentdisclosure may be used to shear each of these different types ofobjects. These objects may be sheared with or without replacement of anyram of the BOP, i.e., a single ram, or a pair of opposing rams, may beused to shear multiple objects in succession. To aid the ram in shearingmultiple objects in succession, the present disclosure provides for anengagement feature to help urge the ram body (e.g., axially) to improveaxial engagement with an opposing ram.

Referring now to FIGS. 2-7, multiple views of opposing shear rams 202and 204 for a shear ram BOP in accordance with one or more embodimentsof the present disclosure are shown. In particular, FIG. 2 provides aside perspective view of the shear rams 202 and 204, and FIG. 3 providesa top down view of the shear rams 202 and 204. Further, FIG. 4 shows across-sectional view of the shear rams 202 and 204 taken along line 4-4in FIG. 2, FIG. 5 shows a detailed view of the engagement of the shearrams 202 and 204 in FIG. 4, FIG. 6 shows a cross-sectional view of theshear rams 202 and 204 taken along line 6-6 in FIG. 2, and FIG. 7 showsa detailed view of the engagement of the shear rams 202 and 204 in FIG.5. The shear rams 202 and 204 may be similar to the rams 24 and 26illustrated in FIGS. 1A-1C, in which the shear ram 202 may be the upperram and the shear ram 204 may be the lower ram.

The shear rams 202 and 204 each include a ram body 206 and 208 that aredefined by a ram back 210 and 212 and a ram front 214 and 216,respectively. The ram backs 210 and 212 are generally configured toreceive a connector rod (not shown), such as the rod 34 shown in FIGS.1A-1C, to move the shear rams 202 and 204 into and out of a BOP bore.The ram fronts 214 and 216 each include a cutting face or blade 218 and220, respectively, configured to shear an object located in a BOP bore.The blade 218 of the upper shear ram 202 is best shown in FIG. 3, andthe blades 218 and 220 of the shear rams 202 and 204 are also shown inFIG. 6.

The shear rams 202 and 204 may further include one or more seals tofacilitate sealing the BOP bore. For example, the rams 202 and 204 mayeach include a top seal 222 and 224 and side seals 226 and 228,respectively. The seals 222-228 may be positioned within cavities orchannels formed within the ram bodies 206 and 208 to maintain the seals222-228 in position as the rams 202 and 204 move within the BOP body.

Further, a seal 250 (e.g., lateral seal), as best shown in FIGS. 4,6,and 7, may be positioned between the blades 218 and 220 of the shearrams 202 and 204. A recess 252 may be formed within one of the shearrams 202 and 204, with the seal 250 positioned within the recess 252.

One or both of the shear rams 202 and 204 may further include anengagement feature 230 and 232, such as located on an outer surface ofthe ram bodies 206 and 208, to urge one or both of the shear rams 202and 204 axially when positioned within the bore of a BOP. In one or moreembodiments, the engagement feature may refer to or include a tapered orangled portion that is used to engage with another component, surface,or corresponding engagement feature. The engagement of the tapered orangled portions upon closing of the shear rams 202 and 204 urges theshear rams axially (e.g., with respect to an axis of a bore of a BOPhousing), such as towards and into engagement with each other.Engagement of the engagement features 230 and 232 also restrictsseparation of the shear rams 202 and 204 to facilitate sealing and/orshearing within the shear ram BOP.

As shown in FIGS. 2-7, both shear rams 202 and 204 may includeengagement features 230 and 232. As the shear rams 202 and 204 move froman open position to a closed position, the engagement features 230 and232 engage with each other. The engagement of the engagement features230 and 232 with each other urges the shear rams 202 and 204 axiallytowards each other and into axial engagement with each other when theshear rams 202 and 204 are located in the BOP bore. The engagementfeatures 230 and 232 may also not engage each other until after anobject within the BOP bore has been sheared by the shear rams 202 and204.

Accordingly, an engagement feature in accordance with the presentdisclosure may facilitate or increase the sealing capability within ashear ram BOP. As mentioned above, the seal 250 may be used to preventfluid flow or debris from flow between the shear rams 202 and 204,particularly when the shear rams 202 and 204 are in the closed positionafter having sheared an object within the shear ram BOP. The engagementfeatures 230 and 232 engage each other after the blades 218 and 220 ofthe shear rams 202 and 204 pass each other and the seal 250 when movinginto the closed position. This engagement of the engagement features 230and 232 urges the shear rams 202 and 204 into axial engagement with eachother, which in turn then activates or further pressurizes the seal 250with the shear rams 202 and 204. This axial engagement of the shear rams202 and 204 may increase the sealing capability of the seal 250.Further, this delayed engagement of the engagement features 230 and 232may help prevent damage to the seal 250, such as from the blades 218 and220 potentially clipping or cutting the seal 250 when passing acrosseach other and the seal 250.

In one or more embodiments in which the shear rams 202 and 204 includecorresponding engagement features 230 and 232, one of the shear rams 202and 204 may include a female engagement feature, and the other of theshear rams 202 and 204 may include a male engagement feature. Forexample, as shown best in FIGS. 4 and 5, the shear ram 202 includes thefemale engagement feature 230 and the shear ram 204 includes the maleengagement feature 232. The engagement feature shown in FIGS. 4 and 5includes a cone-shape (e.g., conical or frusto-conical shape) that formsa portion or surface of the engagement feature. Accordingly, in thisembodiment, the female engagement feature 230 of the shear ram 202 is aconical shaped engagement feature that protrudes into a surface of theshear ram 202, and the male engagement feature 232 of the shear ram 204is a conical shaped engagement feature that protrudes from a surface ofthe shear ram 204. The conical shaped engagement features then engageeach other when the shear rams 202 and 204 are moving into the closedposition to urge the shear rams 202 and 204 axially towards each other.

In one or more of the above embodiments, the engagement features areshown as conical shaped engagement features. However, the presentdisclosure is not so limited, as other shapes, sizes, and arrangementsmay be used for an engagement feature in one or more embodiments. Forexample, in another embodiment, the engagement feature may only includea tapered or angled surface, in which the tapered or angled surfaceengages with another surface (e.g., tapered or not-tapered) to urge theshear ram axially within the shear ram BOP.

Further, in one or more embodiments, to facilitate the engagement andurging of the shear rams 202 and 204 axially towards each other, theengagement features 230 and 232 may be offset from each other. Forexample, as shown in FIG. 5, an apex 234 of the conical shaped femaleengagement feature 230 is offset from an apex 236 of the conical shapedmale engagement feature 232. The apex 234 of the conical shaped femaleengagement feature 230 may be offset by about 0.02 in (about 0.51 mm)from the apex 236 of the conical shaped male engagement feature 232.Accordingly, as the engagement features 230 and 232 are offset from eachother, the offset facilitates engagement between the engagement features230 and 232 as the shear rams 202 and 204 move axially towards and inproximity of each other, thereby urging the shear rams 202 and 204axially towards each other.

The engagement features 230 and 232 may be formed on or coupled to theshear rams 202 and 204. As shown in FIGS. 4 and 5, the engagementfeatures 230 and 232 are formed on the bodies 206 and 208 of the shearrams 202 and 204. However, in another embodiment, the engagementfeatures 230 and 232 may be formed as separate components that areconnected, attached, or otherwise coupled to the bodies 206 and 208 ofthe shear rams 202 and 204. This may facilitate replacing the engagementfeatures 230 and 232, such as if the engagement features 230 and 232become excessively worn or damaged. Further, the engagement features 230and 232 may include or be formed from a hardened material. In oneembodiment, the engagement features 230 and 232 may be heat-treated toharden and otherwise treat the material of the engagement features 230and 232.

The shear rams 202 and 204 may each include more than one engagementfeature. Further, as mentioned above, the engagement features 230 and232 are located on an outer surface of the ram bodies 206 and 208 of theshear rams 202 and 204. Accordingly, in one or more embodiments, theengagement features 230 and 232 are formed or located on opposing (e.g.,inner) faces of the shear rams 202 and 204. The shear rams 202 and 204may each include an upper face 240 and 242 and a lower face 244 and 246,respectively, in which the upper faces 240 and 242 may oppose each otherand the lower faces 244 and 246 may oppose each other. The upper faces240 and 242 of the shear rams 202 and 204 then each includecorresponding upper engagement features 230 and 232 that engage witheach other, and the lower faces 244 and 246 include corresponding lowerengagement features 230 and 232 that engage with each other.

The shear rams 202 and 204 may also include multiple engagement featureson opposite lateral sides (e.g., left and ride sides) of the ram bodies206 and 208. For example, the shear ram 202 may include engagementfeatures 230 positioned on each side of the blade 218 such that theengagement features 230 are positioned adjacent each lateral side of theshear ram 202. Similarly, the shear ram 204 may include engagementfeatures 232 positioned on each side of the blade 220 such that theengagement features 232 are positioned adjacent each lateral side of theshear ram 204. The engagement features 230 of the shear ram 202 may thenengage with the engagement features 232 of the shear ram 204.

As mentioned above, the shear rams 202 and 204 are movable between anopen position and a closed position, in which the shear rams 202 and 204may then shear an object positioned between them or within a BOP borewhen moving from the open positioned to the closed position.Accordingly, the engagement features 230 and 232 of the shear rams 202and 204 may be used to urge the shear rams 202 and 204 into axialengagement with each other when in the closed position. For example,when in the open position, the engagement features 230 and 232 will notengage each other, and thus not urge the shear rams 202 and 204 intoaxial engagement with each other. However, when in the closed position,or closely approaching the closed position, the engagement features 230and 232 engage each other to urge the shear rams 202 and 204 into axialengagement with each other. This urges the shear rams 202 and 204 intoaxial engagement with each other, particularly after shearing an object,and increases the sealing capability of the seal 250 between the shearrams 202 and 204.

In one or more of the above embodiments, the engagement features areshown as formed on each of the shear rams. However, in one or moreembodiments, only one of the shear rams may include an engagementfeature. For example, in such an embodiment, the BOP housing may includea corresponding engagement feature, such as formed internally within theBOP and adjacent the BOP bore. The shear ram engagement feature may thenengage with the BOP engagement feature, such as when the shear ram movestowards the closed position within the BOP housing. This engagement maythen urge the shear ram within the BOP housing, such as axially withinthe BOP housing to facilitate sealing or shearing within the BOP.

As discussed above, a ram and a BOP in accordance with the presentdisclosure may be used to shear one or more objects, including a casingjoint, a drill pipe joint, a tool joint, and a wireline, with eachhaving various shapes, sizes, and/or other dimensions. A casing jointmay have one or more sizes, such as an outer diameter of about 16 inches(about 40.6 centimeters), about 14 inches (about 35.6 centimeters),about 12 inches (about 30.5 centimeters), and/or about 10.625 inches(about 26.99 centimeters). Further, a drill pipe joint may have one ormore sizes, such as an outer diameter of about 6.625 inches (about 16.83centimeters), about 5.5 inches (about 14.0 centimeters), and/or about3.5 inches (about 8.9 centimeters). Moreover, wireline may have one ormore sizes, such as an outer diameter of about 3/16 inches (about 0.47centimeters), about 0.25 inches (about 0.64 centimeters), about 0.5inches (about 1.28 centimeters), and so on. As such, rams and ram bladesof different sizes may be selected to shear on a particular object.Inclusion of a biasing mechanism as discussed above may enhance sealingefficiency in a shear ram BOP, particularly after having sheared anobject.

This discussion is directed to various embodiments of the invention. Thedrawing figures are not necessarily to scale. Certain features of theembodiments may be shown exaggerated in scale or in somewhat schematicform and some details of conventional elements may not be shown in theinterest of clarity and conciseness. Although one or more of theseembodiments may be preferred, the embodiments disclosed should not beinterpreted, or otherwise used, as limiting the scope of the disclosure,including the claims. It is to be fully recognized that the differentteachings of the embodiments discussed may be employed separately or inany suitable combination to produce desired results. In addition, oneskilled in the art will understand that the description has broadapplication, and the discussion of any embodiment is meant only to beexemplary of that embodiment, and not intended to suggest that the scopeof the disclosure, including the claims, is limited to that embodiment.

Certain terms are used throughout the description and claims to refer toparticular features or components. As one skilled in the art willappreciate, different persons may refer to the same feature or componentby different names. This document does not intend to distinguish betweencomponents or features that differ in name but not function, unlessspecifically stated. In the discussion and in the claims, the terms“including” and “comprising” are used in an open-ended fashion, and thusshould be interpreted to mean “including, but not limited to . . . .”Also, the term “couple” or “couples” is intended to mean either anindirect or direct connection. In addition, the terms “axial” and“axially” generally mean along or parallel to a central axis (e.g.,central axis of a body or a port), while the terms “radial” and“radially” generally mean perpendicular to the central axis. The use of“top,” “bottom,” “above,” “below,” and variations of these terms is madefor convenience, but does not require any particular orientation of thecomponents.

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentmay be included in at least one embodiment of the present disclosure.Thus, appearances of the phrases “in one embodiment,” “in anembodiment,” and similar language throughout this specification may, butdo not necessarily, all refer to the same embodiment.

Although the present invention has been described with respect tospecific details, it is not intended that such details should beregarded as limitations on the scope of the invention, except to theextent that they are included in the accompanying claims.

What is claimed is:
 1. A blowout preventer (“BOP”), comprising: ahousing comprising a vertical bore extending through the housing; and apair of opposing shear rams configured to move into the vertical bore,the shear rams comprising an engagement feature configured to engagewith a corresponding engagement feature and urge the shear rams intoaxially towards each other with respect to an axis of the vertical borewhen the shear rams are located in the vertical bore.
 2. The BOP ofclaim 1, further comprising a seal positioned between the opposing ramsand configured to prevent fluid flow therebetween.
 3. The BOP of claim2, wherein the axial movement of the shear rams towards each otherincreases the sealing capability of the seal.
 4. The BOP of claim 2,wherein the seal comprises a lateral seal positioned between blades ofthe shear rams.
 5. The BOP of claim 1, wherein: the pair of opposingshear rams are movable between an open position and a closed position;and the engagement features are configured to urge the shear ramsaxially towards each other when the shear rams are in the closedposition.
 6. The BOP of claim 1, wherein: one of the shear ramscomprises a male engagement feature; and the other of the shear ramscomprises a female engagement feature.
 7. The BOP of claim 6, wherein:the male engagement feature comprises a conical shaped male engagementfeature protruding from a surface of the shear ram; and the femaleengagement feature comprises a corresponding conical shaped femaleengagement feature protruding into a surface of the shear ram.
 8. TheBOP of claim 7, wherein an apex of the conical shaped male engagementfeature is offset from an apex of the conical shaped female engagementfeature.
 9. The BOP of claim 8, wherein the engagement features eachcomprise a tapered engagement feature.
 10. The BOP of claim 1, whereinthe engagement features are formed on opposing inner faces of the shearrams.
 11. The BOP of claim 1, wherein each shear ram comprises aplurality of engagement features.
 12. The BOP of claim 11, wherein: theshear rams comprise opposing upper faces and opposing lower faces; oneof the upper faces comprises an upper engagement feature and the otherof the upper faces comprises a corresponding upper engagement feature;and one of the lower faces comprises a lower engagement feature and theother of the lower faces comprises a corresponding lower engagementfeature.
 13. The BOP of claim 1, wherein the engagement features eachcomprise a hardened material compared to the shear rams.
 14. A shear rampositionable in a blowout preventer (“BOP”) body to move into a verticalbore of the BOP body, the shear ram comprising: a ram body including ashear blade configured to shear an object; and an engagement featureconfigured to urge the ram body axially with respect to an axis of thevertical bore when positioned within the vertical bore of the BOP body.15. The shear ram of claim 14, wherein the engagement feature is furtherconfigured to urge the shear ram axially towards an opposing shear ram.16. The shear ram of claim 15, further comprising a seal positionedbetween the opposing rams to prevent fluid flow therebetween such thatthe axial movements of the shear rams towards each other increases thesealing capability of the seal.
 17. The shear ram of claim 15, whereinthe opposing shear ram comprises a corresponding engagement feature suchthat the engagement features are configured to engage with each otherand urge the shear rams axially towards each other.
 18. The shear ram ofclaim 17, wherein: one of the shear rams comprises a male engagementfeature; and the other of the shear rams comprises a female engagementfeature.
 19. The shear ram of claim 17, wherein the engagement featuresof the shear rams are offset from each other.
 20. The shear ram of claim17, wherein the engagement features are formed on opposing inner facesof the shear rams.